Packaging material for battery

ABSTRACT

A packaging material for batteries including a laminate in which at least a base material layer, a metal layer, and a sealant layer are laminated in order. The battery packaging material satisfies the relationships of: (A1−A2)≥60 N/15 mm; and (B1−B2)≥50 N/15 mm. A1 is a stress in elongation by 10% in the MD direction and B1 is a stress in elongation by 10% in the TD direction in the laminate, and A2 is a stress in elongation by 10% in the MD direction and B2 is a stress in elongation by 10% in the TD direction in the base material layer.

This is a Division of application Ser. No. 15/505,639 filed Feb. 22,2017, which is a National Phase of International Application No.PCT/JP2015/073690 filed Aug. 24, 2015, which claims the benefit ofJapanese Applications Nos. 2014-197013, filed Sep. 26, 2014, and2014-173870, filed Aug. 28, 2014. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentireties.

TECHNICAL FIELD

The present invention relates to a battery packaging material havingexcellent moldability with pinholes and cracks hardly generated duringmolding. The present invention also relates to a battery packagingmaterial in which curling after molding is suppressed.

BACKGROUND ART

Various types of batteries have been developed heretofore, and in everybattery, a packaging material is an essential member for sealing batteryelements such as an electrode and an electrolyte. Metallic packagingmaterials have been often used heretofore as battery packagings.

On the other hand, in recent years, batteries have been required to bediversified in shape and to be thinned and lightened with improvement ofperformance of electric cars, hybrid electric cars, personal computers,cameras, mobile phones and so on. However, metallic battery packagingmaterials that have often been heretofore used have the disadvantagethat it is difficult to keep up with diversification in shape, and thereis a limit on weight reduction.

Thus, in recent years, there has been proposed a film-shaped laminatewith a base material, a metal layer and a sealant layer laminated inthis order has been proposed as a battery packaging material which iseasily processed into diversified shapes and is capable of achievingthickness reduction and weight reduction. However, such a film-shapedpackaging material is thinner as compared to a metallic packagingmaterial, and has the disadvantage that pinholes and cracks are easilygenerated during molding. If pinholes and cracks are generated in abattery packaging material, an electrolytic solution may permeate to ametal layer to form a metal precipitate, resulting in generation of ashort-circuit, and therefore it is absolutely necessary that afilm-shaped battery packaging material have a property that makes ithard to generate pinholes during molding, i.e. excellent moldability.

Various studies have been conducted heretofore with attention paid to anadhesive layer for bonding a metal layer in order to improve themoldability of a film-shaped battery packaging material. For example,Patent Document 1 discloses that in a laminated packaging material whichincludes an inner layer including a resin film; a first adhesive agentlayer; a metal layer; a second adhesive agent layer; and an outer layerincluding a resin film, at least one of the first adhesive agent layerand the second adhesive agent layer is formed of an adhesive agentcomposition containing a resin having an active hydrogen group on theside chain, a polyfunctional isocyanate and a polyfunctional aminecompound to give a packaging material having high reliability in deepermolding.

As represented by Patent Document 1, many studies have been conductedheretofore on techniques for improving moldability with attention paidto blended components of an adhesive layer for bonding a metal layer andother layer in a battery packaging material including a film-shapedlaminate, but there have been reported very few techniques for improvingmoldability with attention paid to the properties of the batterypackaging material as a whole.

PRIOR ART DOCUMENTS Patent Document

-   Patent Document 1: Japanese Patent Laid-open Publication No.    2008-287971

Non-Patent Document

-   Non-Patent Document 1: Akira Ota, “Press Processing Engineering    Manual”, published by NIKKAN KOGYO SHIMBUN, LTD., issued on Jul. 30,    1981, pages 1 to 3

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

A first object of the present invention is to provide the followingtechnique: a battery packaging material including a film-shaped laminatein which at least a base material layer, a metal layer and a sealantlayer are laminated in this order has excellent moldability with cracksand pinholes hardly generated during molding.

In recent years, it has been required to further increase the energydensity of a battery, and further reduces the size of the battery. Forincreasing the energy density of the battery, the molding depth of thebattery packaging material may be made larger to increase the capacityof a battery element that can be stored in the battery packagingmaterial. However, when the molding depth of the battery packagingmaterial is excessively large, a stress applied to the packagingmaterial increases, and a difference between a stress applied to anouter layer and a stress applied to an inner layer also increases. Whenthe thickness is excessively small, shape retainability is deteriorated.Further, when there is an excessively large difference in slippagebetween the inner layer and the outer layer, how the outer layer isdrawn is different from how the inner layer is drawn during molding.Accordingly, due to these factors and the like, the peripheral edge of arecess portion formed on the battery packaging material is curled(curved), so that storage of a battery element and heat-sealing of asealant layer may be hindered, leading to deterioration of productionefficiency of the battery.

Under these circumstances, a second object of the present invention isto provide the following technique: curling after molding is suppressedin a battery packaging material including a laminate in which at least abase material layer, a metal layer and a sealant layer are laminated inthis order.

Means for Solving the Problems

The present inventors have extensively conducted studies for achievingthe above-mentioned first object. Resultantly, the present inventorshave found that when a battery packaging material including a laminatein which a base material layer, a metal layer and a sealant layer arelaminated in this order satisfies the relationship of A+B≥2.50, whereA+B is a sum of a value A of a ratio of a stress in elongation by 40% toa stress in elongation by 10% in the MD direction and a value B of aratio of a stress in elongation by 40% to a stress in elongation by 10%in the TD direction in the laminate, unexpectedly outstandinglyexcellent moldability can be imparted to a battery packaging material,so that the ratio of generation of pinholes and cracks during moldingcan be considerably reduced. A first aspect of the present invention hasbeen completed by further conducting studies based on theabove-mentioned findings.

The present inventors have extensively conducting studies for achievingthe above-mentioned second object. Resultantly, the present inventorshave found that when a battery packaging material including a laminatein which a base material layer, a metal layer and a sealant layer arelaminated in this order satisfies the relationships of (A1−A2)≥60 N/15mm and (B1−B2)≥50 N/15 mm, where A1 is a stress in elongation by 10% inthe MD direction and B1 is a stress in elongation by 10% in the TDdirection in the laminate, and A2 is a stress in elongation by 10% inthe MD direction and B2 is a stress in elongation by 10% in the TDdirection in the base material layer, unexpectedly curling after moldingcan be effectively suppressed. A second aspect of the present inventionhas been completed by further conducting studies based on theabove-mentioned findings.

That is, the present invention provides a battery packaging material anda battery of the following aspects.

Item 1. A battery packaging material including a laminate in which atleast a base material layer, a metal layer and a sealant layer arelaminated in this order,

the laminate satisfying the relationship of A+B≥2.50, where A+B is a sumof a value A of a ratio of a stress in elongation by 40% to a stress inelongation by 10% in the MD direction and a value B of a ratio of astress in elongation by 40% to a stress in elongation by 10% in the TDdirection.

Item 2. The battery packaging material according to item 1, wherein thevalue A and the value B satisfy the relationship of A<B.

Item 3. The battery packaging material according to item 1 or 2, whereinthe value A is 1.19 or more, and the value B is 1.31 or more.

Item 4. The battery packaging material according to any one of items 1to 3, wherein the tensile rupture strength of the base material layer ineach of the MD direction and the TD direction is 200 MPa or more, andthe tensile rupture elongation of the base material layer in each of theMD direction and the TD direction is in the range of 70 to 130%.Item 5. The battery packaging material according to any one of items 1to 4, wherein the metal layer is an aluminum foil in which the 0.2%yield strength when a tensile test is conducted in a direction parallelto the MD direction and the 0.2% yield strength when a tensile test isconducted in a direction parallel to the TD direction are each in therange of 55 to 140 N/mm².Item 6. The battery packaging material according to any one of items 1to 5, wherein the base material layer is formed of at least one of apolyamide resin and a polyester resin.Item 7. A battery packaging material including a laminate in which atleast a base material layer, a metal layer and a sealant layer arelaminated in this order, wherein

when A1 is a stress in elongation by 10% in the MD direction and B1 is astress in elongation by 10% in the TD direction in the laminate, and

A2 is a stress in elongation by 10% in the MD direction and B2 is astress in elongation by 10% in the TD direction in the base materiallayer,

the battery packaging material satisfies the relationships of:(A1−A2)≥60 N/15 mm; and

(B1−B2)≥50 N/15 mm.

Item 8. The battery packaging material according to claim 7, wherein theratio of (A1-A2) to (B1−B2) satisfies the relationship of(A1−A2)/(B1−B2)=1.00 to 1.20.

Item 9. The battery packaging material according to claim 7 or 8,wherein, when C is a dynamic friction coefficient of a surface of thebase material layer and D is a dynamic friction coefficient of a surfaceof the sealant layer,

the battery packaging material satisfies the relationships of: C≤0.3;

D≤0.3; and

C/D=0.5 to 2.5.

Item 10. The battery packaging material according to any one of claims 7to 9, wherein the battery packaging material is a battery packagingmaterial for deep drawing which is molded with a molding depth of 4 mmor more.

Item 11. The battery packaging material according to any one of claims 7to 10, wherein the laminate has a thickness of 120 μm or less.

Item 12. The battery packaging material according to any one of items 1to 11, wherein at least one surface of the metal layer is subjected to achemical conversion treatment.

Item 13. The battery packaging material according to any one of items 1to 12, wherein the battery packaging material is a packaging materialfor a secondary battery.

Item 14. A battery, wherein a battery element including at least apositive electrode, a negative electrode and an electrolyte is stored inthe battery packaging material according to any one of items 1 to 13.

Advantages of the Invention

The battery packaging material according to a first aspect of thepresent invention satisfies the relationship of A+B≥2.50, where A+B is asum of a value A of a ratio of a stress in elongation by 40% to a stressin elongation by 10% in the MD direction and a value B of a ratio of astress in elongation by 40% to a stress in elongation by 10% in the TDdirection in the battery packaging material as a whole, and thusgeneration of pinholes, cracks and the like during molding of thebattery packaging material can be suppressed. Further, the batterypackaging material according to the first aspect of the presentinvention has excellent moldability as described above, and thereforecan contribute to improvement of productivity.

The battery packaging material according to a second aspect of thepresent invention satisfies the relationships of (A1−A2)≥60 N/15 mm and(B1−B2)≥50 N/15 mm, where A1 is a stress in elongation by 10% in the MDdirection and B1 is a stress in elongation by 10% in the TD direction ina laminate, and A2 is a stress in elongation by 10% in the MD directionand B2 is a stress in elongation by 10% in the TD direction in a basematerial layer, and thus curling after molding can be effectivelysuppressed. Further, the battery packaging material according to thesecond aspect of the present invention can also contribute toimprovement of productivity of batteries because curling after moldingis suppressed, so that storage of a battery element and heat-sealing ofa sealant layer are hardly hindered.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing one example of a cross-sectional structureof a battery packaging material according to a first aspect of thepresent invention.

FIG. 2 is a drawing showing one example of a cross-sectional structureof the battery packaging material according to the first aspect of thepresent invention.

FIG. 3 is a schematic view for explaining a relationship between stressand strain during molding of a battery packaging material regarding tothe first aspect of the present invention.

FIG. 4 is a drawing showing one example of a cross-sectional structureof the battery packaging material according to a second aspect of thepresent invention.

FIG. 5 is a drawing showing one example of a cross-sectional structureof a battery packaging material according to the second aspect of thepresent invention.

FIG. 6 is a schematic view for explaining a method for evaluation oncurling.

FIG. 7 is a schematic view for explaining a method for evaluation oncurling.

EMBODIMENTS OF THE INVENTION

A battery packaging material according to a first aspect of the presentinvention includes a laminate in which at least a base material layer, ametal layer and a sealant layer are laminated in this order, the basematerial layer satisfying the relationship of A+B≥2.50, where A+B is asum of a value A of a ratio of a stress in elongation by 40% to a stressin elongation by 10% in the MD direction and a value B of a ratio of astress in elongation by 40% to a stress in elongation by 10% in the TDdirection.

A battery packaging material according to a second aspect of the presentinvention includes a laminate in which at least a base material layer, ametal layer and a sealant layer are laminated in this order, wherein

when A1 is a stress in elongation by 10% in the MD direction and B1 is astress in elongation by 10% in the TD direction in the laminate, and

A2 is a stress in elongation by 10% in the MD direction and B2 is astress in elongation by 10% in the TD direction in the base materiallayer,

the battery packaging material satisfies the relationships of:(A1−A2)≥60 N/15 mm; and

(B1−B2)≥50 N/15 mm.

Hereinafter, the battery packaging materials according to the firstaspect and the second aspect of the present invention will be describedin detail.

1. Laminated Structure of Battery Packaging Material

The battery packaging material according to the first aspect of thepresent invention includes a laminate in which at least a base materiallayer 1, a metal layer 3 and a sealant layer 4 are laminated in thisorder as shown in FIG. 1. In the battery packaging material according tothe first aspect of the present invention, the base material layer 1 isan outermost layer, and the sealant layer 4 is an innermost layer. Thatis, at the time of assembling a battery, the sealant layer 4 situated onthe periphery of a battery element is heat-welded with itself tohermetically seal the battery element, so that the battery element isencapsulated.

As shown in FIG. 1 and FIG. 2, the battery packaging material accordingto the first aspect of the present invention may be provided with anadhesive layer 2 between the base material layer 1 and the metal layer 3as necessary in order to improve adhesion of these layers. As shown inFIG. 2, the battery packaging material according to the first aspect ofthe present invention may be provided with an adhesive layer 5 betweenthe metal layer 3 and the sealant layer 4 as necessary in order toimprove adhesiveness of these layers.

The battery packaging material according to the second aspect of thepresent invention includes a laminate in which at least a base materiallayer 1, a metal layer 3 and a sealant layer 4 are laminated in thisorder as shown in FIG. 4. In the battery packaging material according tothe second aspect of the present invention, the base material layer 1 isan outermost layer, and the sealant layer 4 is an innermost layer. Thatis, at the time of assembling a battery, the sealant layer 4 situated onthe periphery of a battery element is heat-welded with itself tohermetically seal the battery element, so that the battery element isencapsulated.

As shown in FIG. 4 and FIG. 5, the battery packaging material accordingto the second aspect of the present invention may be provided with anadhesive layer 2 between the base material layer 1 and the metal layer 3as necessary in order to improve adhesion of these layers. As shown inFIG. 5, the battery packaging material according to the second aspect ofthe present invention may be provided with an adhesive layer 5 betweenthe metal layer 3 and the sealant layer 4 as necessary in order toimprove adhesiveness of these layers. A coating layer may be provided ona surface (surface on a side opposite to the sealant layer 4) of thebase material layer 1 although not illustrated.

2. Properties of Battery Packaging Material

The battery packaging material according to the first aspect of thepresent invention satisfies the relationship of A+B≥2.50, where A+B is asum of a value A of a ratio of a stress in elongation by 40% to a stressin elongation by 10% in the MD direction and a value B of a ratio of astress in elongation by 40% to a stress in elongation by 10% in the TDdirection in the laminate that forms the battery packaging material.Specifically, the battery packaging material satisfies the relationshipof A+B≥2.50, where A+B is a sum of the value A of a ratio of a stress inelongation by 40% to a stress in elongation by 10% in the machinedirection (MD direction) and the value B of a ratio of a stress inelongation by 40% to a stress in elongation by 10% in the verticaldirection (TD direction) that is coplanar with the MD direction in thelaminate that forms the battery packaging material. When the batterypackaging material is a roll of a sheet-shaped laminate, the lengthdirection (unwinding direction) in the laminate is the MD direction andthe width direction in the laminate is the TD direction at the time ofunwinding the laminate from the roll. In the first aspect of the presentinvention, the stress in elongation by 40% and the stress in elongationby 10% in each of the MD direction and the TD direction in the laminateare values measured in accordance with a method as specified in JISK7127.

In the battery packaging material according to the first aspect of thepresent invention, stresses in the MD direction and the TD direction inthe laminate satisfy the above-mentioned relationship, so thatgeneration of pinholes, cracks and the like during molding issuppressed, and thus the battery packaging material has excellentmoldability. The detailed mechanism in which when the properties as awhole of the battery packaging material according to the first aspect ofthe present invention are set in the manner described above, generationof pinholes, cracks and the like during molding is suppressed is not allevident, but may be considered as follows, for example. The values A andB of the ratio of a stress in elongation by 40% to a stress inelongation by 10% in the MD direction and the TD direction are largeenough to satisfy the relationship of A+B≥2.50. Accordingly, for exampleas shown by the line A in FIG. 3, i.e. a schematic view showing arelationship between stress and strain during molding of the batterypackaging material, a change in stress around the yield point in astress-strain curve is gentle, so that rapid deformation (extension) ofthe battery packaging material is suppressed, and resultantlydeformation (extension) of the metal layer 3 can be gently changed.Accordingly, it is considered that during molding of the batterypackaging material, the metal layer 3 can be made to properly follow theshape of a mold, so that generation of pinholes, cracks and the like issuppressed. The upper limit of the value of A+B is normally about 3.50.

On the other hand, when the value of A+B is less than 2.50 in thebattery packaging material, a change in stress around the yield point inthe stress-strain curve is large as shown by the line B in FIG. 3, andtherefore deformation (extension) of the battery packaging material isgreatly changed. Accordingly, it is considered that during molding ofthe battery packaging material, the metal layer 3 is hardly made toproperly follow the shape of a mold, so that pinholes, cracks and thelike are easily generated.

For suppressing pinholes, cracks and the like during molding of thebattery packaging material according to the first aspect of the presentinvention to further improve moldability, the battery packaging materialparticularly preferably satisfies the relationship of A+B≥2.65. Further,from the same point of view, it is preferable that the value A and thevalue B satisfy the relationship of A<B. From the same point of view, itis preferable that the value A is 1.19 or more, and the value B is 1.31or more, and it is particularly preferable that the value A is 1.24 ormore, and the value B is 1.47 or more.

In the first aspect of the present invention, the value of a stress inelongation by 40% in the MD direction in the battery packaging materialis not particularly limited, but it is preferably about 40 to 90 MPa,more preferably about 60 to 80 MPa. The stress in elongation by 40% inthe TD direction in the battery packaging material is not particularlylimited, but it is preferably about 50 to 100 MPa, more preferably about60 to 80 MPa. The stress in elongation by 10% in the MD direction in thebattery packaging material is not particularly limited, but it ispreferably about 30 to 70 MPa, more preferably about 45 to 60 MPa. Thestress in elongation by 10% in the TD direction in the battery packagingmaterial is not particularly limited, but it is preferably about 20 to60 MPa, more preferably about 40 to 55 MPa.

For setting the properties of the battery packaging material accordingto the first aspect of the present invention to specific values asdescribed above, the composition, properties, thickness and so on ofeach of the base material layer 1, the metal layer 3 and the sealantlayer 4 that form the battery packaging material may be appropriatelyadjusted.

The battery packaging material according to the second aspect of thepresent invention satisfies the relationships of (A1−A2)≥60 N/15 mm and(B1−B2)≥50 N/15 mm, where A1 is a stress in elongation by 10% in the MDdirection that forms the battery packaging material, and B1 is a stressin elongation by 10% in the TD direction, and A2 is a stress inelongation by 10% in the MD direction and B2 is a stress in elongationby 10% in the TD direction in the base material layer 1. Specifically,the battery packaging material satisfies the relationship of (A1−A2)≥60N/15 mm, where A1−A2 is a difference between the value A1 of a stress inelongation by 10% in the machine direction (MD direction) in thelaminate that forms the battery packaging material and the value A2 of astress in elongation by 10% in the machine direction (MD direction) inthe resin film that forms the base material layer 1, and further, thebattery packaging material satisfies the relationship of (B1−B2)≥50 N/15mm, where B1−B2 is a difference between the value B1 of a stress inelongation by 10% in the vertical direction (TD direction) that iscoplanar with the MD direction in the laminate that forms the batterypackaging material and the value B2 of a stress in elongation by 10% inthe vertical direction (TD direction) that is coplanar with the MDdirection in the resin film that forms the base material layer 1. Whenthe battery packaging material is a roll of a sheet-shaped laminate, thelength direction (unwinding direction) in the laminate is the MDdirection and the width direction in the laminate is the TD direction atthe time of unwinding the laminate from the roll. In the second aspectof the present invention, the stress in elongation by 10% in each of theMD direction and the TD direction in each of the laminate and the basematerial layer 1 is a value measured in accordance with a method asspecified in JIS K7127.

In the battery packaging material according to the second aspect of thepresent invention, stresses in the MD direction and the TD direction inthe laminate and the base material layer 1 that form the batterypackaging material satisfy a specific relationship as described above,and thus curling after molding is effectively suppressed. The detailedmechanism in which in the battery packaging material according to thesecond aspect of the present invention, curling after molding iseffectively suppressed because the laminate and the base material layer1 have a relationship as described above is not all evident, but may beconsidered as follows, for example. That is, it is considered that whenthe difference (A1−A2) and the difference (B1−B2) in stress inelongation by 10% in the MD direction and TD direction between the wholeof the laminate that forms the battery packaging material and the basematerial layer 1 that is a part of the laminate are each larger than aspecific value, an impact given to the whole of the battery packagingmaterial by a change in shape of the base material layer 1 duringmolding is reduced, so that curling (curvature) of the battery packagingmaterial due to a change in shape of the base material layer 1 on theperiphery of a recess portion formed by molding is suppressed.

In the second aspect of the present invention, evaluation on curling ofthe battery packaging material after molding can be performed by amethod as described in examples (see FIG. 6 and FIG. 7).

In the second aspect of the present invention, it is preferable tosatisfy the relationship of (A1−A2)≥62 N/15 mm for further effectivelysuppressing curling of the battery packaging material after molding.From the same point of view, it is preferable to satisfy therelationship of (B1−B2)≥55 N/15 mm. The upper limit of the value ofA1−A2 is normally 80 N/15 mm. The upper limit of the value of B1−B2 isnormally 70 N/15 mm.

Further, in the second aspect of the present invention, the ratio of(A1−A2) to (B1−B2) satisfies preferably the relationship of(A1−A2)/(B1−B2)=1.00 to 1.20, more preferably the relationship of(A1−A2)/(B1−B2)=1.00 to 1.15 for further effectively suppressing curlingof the battery packaging material after molding.

In the second aspect of the present invention, it is preferable tosatisfy the following relationships:

C≤0.3, D≤0.3 and C/D=0.5 to 2.5, where C is a dynamic frictioncoefficient of a surface of the base material layer 1 (a surface of acoating layer if the base material layer has the coating layer), and Dis a dynamic friction coefficient of a surface of the sealant layer 4,for further effectively suppressing curling of the battery packagingmaterial after molding. When the dynamic friction coefficient of each ofboth surfaces of the battery packaging material is smaller than theabove-mentioned value, and the ratio of the dynamic frictioncoefficients on both surfaces is in a predetermined range, the balanceof change in shape of the battery packaging material during molding isimproved, and resultantly curling after molding can be furthersuppressed. From the same point of view, it is more preferable tosatisfy the relationships of C≤0.25, D≤0.20 and C/D=0.8 to 2.0. Thedynamic friction coefficient C of a surface of the base material layer 1and the dynamic friction coefficient D of a surface of the sealant layer4 are each measured by a method conforming to JIS K7125.

The battery packaging material according to the second aspect of thepresent invention can contribute to improvement of productivity ofbatteries because curling after molding is effectively suppressed.Therefore, the battery packaging material according to the second aspectof the present invention can be suitably used as a battery packagingmaterial for deep drawing which is molded with a molding depth of 4 mmor more, preferably about 6 to 12 mm. Since the battery packagingmaterial according to the second aspect of the present invention can beeffectively used as a battery packaging material for deep drawing, thecapacity of a battery element that can be stored in the batterypackaging material can be increased. Thus, the battery packagingmaterial can contribute to improvement of the energy density of thebattery.

In the battery packaging material according to the second aspect of thepresent invention, curling after molding is effectively suppressed evenwhen the laminate that forms the battery packaging material has a smallthickness of, for example, 120 μm or less, or even about 60 to 110 μm.Accordingly, even when the thickness is reduced, the battery packagingmaterial according to the second aspect of the present invention cancontribute to improvement of the energy density of the battery whilesuppressing deterioration of productivity of the battery.

For setting the properties of the laminate and the base material layer 1of the battery packaging material according to the second aspect of thepresent invention to the above-mentioned relationships, the composition,properties, thickness and so on of each of the base material layer 1,the metal layer 3 and the sealant layer 4 that form the batterypackaging material may be appropriately adjusted. Hereinafter, thelayers that form the battery packaging materials according to the firstaspect and the second aspect of the present invention will be describedin detail.

3. Composition of Each Layer Forming Battery Packaging Material

[Base Material Layer 1]

In the battery packaging material according to the first aspect and thesecond aspect of the present invention, the base material layer 1 is alayer that forms the outermost layer. The material that forms the basematerial layer 1 is not particularly limited as long as it hasinsulation quality. Examples of the material that forms the basematerial layer 1 include resin films of polyester resin, polyamideresin, epoxy resin, acrylic resin, fluororesin, polyurethane resin,silicone resin, phenol resin and mixtures and copolymers thereof. Amongthem, polyester resins and polyamide resins are preferred, and biaxiallystretched polyester resins and biaxially stretched polyamide resins aremore preferred. Specific examples of the polyester resin includepolyethylene terephthalate, polybutylene terephthalate, polyethylenenaphthalate, polybutylene naphthalate, copolyester and polycarbonate.Specific examples of the polyamide resin include nylon 6, nylon 6,6,copolymer of nylon 6 and nylon 6,6, nylon 6,10, andpolymethaxylyleneadipamide (MXD6).

Preferably, the base material layer 1 (resin film that forms the basematerial layer 1) has a tensile rupture strength of 200 MPa or more ineach of the MD direction and the TD direction, and a tensile ruptureelongation of 70 to 130% in each of the MD direction and the TDdirection. More preferably, the base material layer has a tensilerupture strength of 250 to 380 MPa in each of the MD direction and theTD direction, and a tensile rupture elongation of 80 to 125% in each ofthe MD direction and the TD direction. When the tensile rupture strengthand the tensile rupture elongation of the base material layer 1 havevalues as described above, the values A and B for the battery packagingmaterials according to the first aspect and the second aspect of thepresent invention can be suitably set to the above-mentionedrelationships, so that generation of pinholes and cracks during moldingcan be further effectively suppressed to further improve moldability.The tensile rupture strength and the tensile rupture elongation of thebase material layer 1 are each obtained by performing measurement by amethod conforming to JIS K7127.

The base material layer 1 may be formed of a single layer resin film, ormay be formed of a resin film having two or more layers for improvingpinhole resistance and an insulation quality. When the base materiallayer 1 is to be formed of a multilayer resin film, two or more resinfilms may be laminated together with an adhesive component such as anadhesive agent or an adhesive resin interposed therebetween, and thekind, amount and so on of the adhesive component to be used are similarto those for the later-described adhesive layer 2 or adhesive layer 5.The method for laminating a resin film having two or more layers is notparticularly limited, and a known method can be employed. Examplesthereof include a dry lamination method and a sand lamination method,and a dry lamination method is preferred. When the resin film islaminated by a dry lamination method, it is preferred to use aurethane-based adhesive agent as the adhesive layer. Here, the thicknessof the adhesive layer is, for example, about 2 to 5 μm.

While the thickness of the base material layer 1 is not particularlylimited as long as a function as a base material layer is performed, andthe battery packaging material satisfies the above-mentioned properties,it is, for example, about 10 to 50 μm, preferably about 15 to 25 μm.

[Adhesive Layer 2]

In the battery packaging materials according to the first aspect and thesecond aspect of the present invention, the adhesive layer 2 is a layerprovided between the base material layer 1 and the metal layer 3 asnecessary for strongly bonding these layers to each other.

The adhesive layer 2 is formed from an adhesive capable of bonding thebase material layer 1 and the metal layer 3. The adhesive used forforming the adhesive layer 2 may be a two-liquid curable adhesive, ormay be a one-liquid curable adhesive. Further, the adhesion mechanism ofthe adhesive used for forming the adhesive layer 2 is not particularlylimited, and may be any one of a chemical reaction type, a solventvolatilization type, a heat melting type, a heat pressing type and soon.

Specific examples of the adhesive component that can be used for formingthe adhesive layer 2 include polyester-based resins such as polyethyleneterephthalate, polybutylene terephthalate, polyethylene naphthalate,polybutylene naphthalate, polyethylene isophthalate, polycarbonate andcopolymerized polyester; polyether-based adhesive agents;polyurethane-based adhesive agents; epoxy-based resins; phenolresin-based resins; polyamide-based resins such as nylon 6, nylon 66,nylon 12 and copolymerized polyamide; polyolefin-based resins such aspolyolefins, carboxylic acid-modified polyolefins and metal-modifiedpolyolefins, polyvinyl acetate-based resins; cellulose-based adhesiveagents; (meth)acryl-based resins; polyimide-based resins; amino resinssuch as urea resins and melamine resins; rubbers such as chloroprenerubber, nitrile rubber and styrene-butadiene rubber; and silicone-basedresins. These adhesive components may be used alone, or may be used incombination of two or more thereof. Among these adhesive components,polyurethane-based adhesives are preferred.

While the thickness of the adhesive layer 2 is not particularly limitedas long as a function as an adhesive layer is performed, and the batterypackaging material satisfies the above-mentioned properties, it is, forexample, about 1 to 10 μm, preferably about 2 to 5 μm.

[Metal Layer 3]

In the battery packaging material, the metal layer 3 is a layer that isintended to improve the strength of the battery packaging material, andalso functions as a barrier layer for preventing ingress of water vapor,oxygen, light and the like into the battery. Specific examples of themetal forming the metal layer 3 include aluminum, stainless andtitanium, with aluminum being preferred. The metal layer 3 can be formedfrom a metal foil or by metal deposition, and is preferably formed froma metal foil, more preferably from an aluminum foil. From the view pointof preventing generation of wrinkles, pinholes and the like in the metallayer 3 during production of the battery packaging material, it is morepreferred to form from soft aluminum foil such as annealed aluminum (JISA8021P-O, JIS A8079P-O).

The aluminum foil to be used as the metal layer 3, the 0.2% yieldstrength when a tensile test is conducted in a direction parallel to theMD direction and the 0.2% yield strength when a tensile test isconducted in a direction parallel to the TD direction are eachpreferably in the range of 55 to 140 N/mm², more preferably in the rangeof 60 to 100 N/mm². The 0.2% yield strength is measured by a tensiletest defined in JIS Z 2241 (total elongation method).

While the thickness of the metal layer 3 is not particularly limited aslong as a function as a metal layer is performed, and the batterypackaging material satisfies the above-mentioned properties, it may be,for example, about 10 to 50 μm, preferably about 20 to 40 μm.

Preferably, at least one surface, preferably both surfaces, of the metallayer 3 are subjected to a chemical conversion treatment forstabilization of bonding, prevention of dissolution and corrosion, andso on. Here, the chemical conversion treatment is a treatment forforming an acid resistance film on the surface of the metal layer.

Examples of the chemical conversion treatment include a chromic acidchromate treatment using a chromic acid compound such as chromiumnitrate, chromium fluoride, chromium sulfate, chromium acetate, chromiumoxalate, chromium biphosphate, acetylacetate chromate, chromium chlorideor chromium potassium sulfate; a phosphoric acid chromate treatmentusing a phosphoric acid compound such as sodium phosphate, potassiumphosphate, ammonium phosphate or polyphosphoric acid; and a chromatetreatment using an aminated phenol polymer having repeating unitsrepresented by the following general formulae (1) to (4).

In the general formulae (1) to (4), X represents a hydrogen atom, ahydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group ora benzyl group. R¹ and R² are the same or different, and each representsa hydroxyl group, an alkyl group or a hydroxyalkyl group. In the generalformulae (1) to (4), examples of the alkyl group represented by X, R¹and R² include linear or branched alkyl groups with a carbon number of 1to 4, such as a methyl group, an ethyl group, a n-propyl group, anisopropyl group, a n-butyl group, an isobutyl group and a tert-butylgroup. Examples of the hydroxyalkyl group represented by X, R¹ and R²include linear or branched alkyl groups with a carbon number of 1 to 4,which is substituted with one hydroxy group, such as a hydroxymethylgroup, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropylgroup, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group anda 4-hydroxybutyl group. In the general formulae (1) to (4), the alkylgroup and the hydroxyalkyl group represented by X, R¹ and R² may be thesame or different. In the general formulae (1) to (4), X is preferably ahydrogen atom, a hydroxyl group or a hydroxyalkyl group. A numberaverage molecular weight of the aminated phenol polymer having repeatingunits represented by the general formulae (1) to (4) is preferably about500 to 1000000, and more preferably about 1000 to 20000, for example.

Examples of the chemical conversion treatment method for impartingcorrosion resistance to the metal layer 3 include a method in which themetal layer 3 is coated with a dispersion of fine particles of a metaloxide such as aluminum oxide, titanium oxide, cerium oxide or tin oxideor barium sulfate in phosphoric acid, and annealed at 150° C. or higherto form corrosion resistance treatment layer on the surface of the metallayer 3. A resin layer with a cationic polymer crosslinked with acrosslinking agent may be further formed on the corrosion resistancetreatment layer. Here, examples of the cationic polymer includepolyethyleneimine, ion polymer complexes formed of a polymer havingpolyethyleneimine and a carboxylic acid, primary amine-grafted acrylicresins obtained by graft-polymerizing a primary amine with an acrylicmain backbone, polyallylamine or derivatives thereof, and aminophenol.These cationic polymers may be used alone, or may be used in combinationof two or more thereof. Examples of the crosslinking agent includecompounds having at least one functional group selected from the groupconsisting of an isocyanate group, a glycidyl group, a carboxyl groupand an oxazoline group, and silane coupling agents. These crosslinkingagents may be used alone, or may be used in combination of two or morethereof.

As for the chemical conversion treatment, only one chemical conversiontreatment may be conducted, or combination of two or more chemicalconversion treatments may be conducted. The chemical conversiontreatments may be performed using one compound alone, or may beperformed using two or more compounds in combination. Among chemicalconversion treatments, a chromic acid chromate treatment, a chromatetreatment using a chromic acid compound, a phosphoric acid compound andan aminated phenol polymer in combination, and so on are preferred.

The amount of the acid resistance film to be formed on the surface ofthe metal layer 3 in the chemical conversion treatment is notparticularly limited, but for example, when the above-mentioned chromatetreatment is performed, it is desirable that the chromic acid compoundbe contained in an amount of about 0.5 mg to about 50 mg, preferablyabout 1.0 mg to about 40 mg, in terms of chromium, the phosphoruscompound be contained in an amount of about 0.5 mg to about 50 mg,preferably about 1.0 mg to about 40 mg, in terms of phosphorus, and theaminated phenol polymer be contained in an amount of about 1 mg to about200 mg, preferably about 5.0 mg to 150 mg, per 1 m² of the surface ofthe metal layer 3.

The chemical conversion treatment is performed in the following manner:a solution containing a compound to be used for formation of an acidresistance film is applied onto the surface of the metal layer by a barcoating method, a roll coating method, a gravure coating method, animmersion method or the like, and heating is then performed so that thetemperature of the metal layer is about 70° C. to 200° C. The metallayer may be subjected to a degreasing treatment by an alkali immersionmethod, an electrolytic cleaning method, an acid cleaning method, anelectrolytic acid cleaning method or the like before the metal layer issubjected to a chemical conversion treatment. When a degreasingtreatment is performed as described above, the chemical conversiontreatment of the surface of the metal layer can be further efficientlyperformed.

[Sealant Layer 4]

In the battery packaging materials according to the first aspect and thesecond aspect of the present invention, the sealant layer 4 correspondsto the innermost layer, and during assembly of a battery, the sealantlayers are heat-welded to each other to hermetically seal the batteryelement.

The resin component to be used in the sealant layer 4 is notparticularly limited as long as it can be heat-welded, and examplesthereof include polyolefins, cyclic polyolefins, carboxylicacid-modified polyolefins and carboxylic acid-modified cyclicpolyolefins.

Specific examples of the polyolefin include polyethylene such aslow-density polyethylene, medium-density polyethylene, high-densitypolyethylene and linear low-density polyethylene; polypropylene such ashomopolypropylene, block copolymers of polypropylene (e.g. blockcopolymers of propylene and ethylene) and random copolymers ofpolypropylene (e.g. random copolymers of propylene and ethylene);terpolymers of ethylene-butene-propylene; and the like. Among thesepolyolefins, polyethylenes and polypropylenes are preferred.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer,and examples of the olefin as a constituent monomer of the cyclicpolyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene,butadiene and isoprene. Examples of the cyclic monomer as a constituentmonomer of the cyclic polyolefin include cyclic alkenes such asnorbornene, specifically cyclic dienes such as cyclopentadiene,dicyclopentadiene, cyclohexadiene and norbornadiene. Among thesepolyolefins, cyclic alkenes are preferred, and norbornene is furtherpreferred.

The carboxylic acid-modified polyolefin is a polymer with the polyolefinmodified by subjecting the polyolefin to block polymerization or graftpolymerization with a carboxylic acid. Examples of the carboxylic acidto be used for modification include maleic acid, acrylic acid, itaconicacid, crotonic acid, maleic anhydride and itaconic anhydride.

The carboxylic acid-modified cyclic polyolefin is a polymer obtained byperforming copolymerization with an α,β-unsaturated carboxylic acid oran anhydride thereof replacing a part of monomers that form the cyclicpolyolefin, or by block-polymerizing or graft-polymerizing anα,β-unsaturated carboxylic acid or an anhydride thereof with the cyclicpolyolefin. The cyclic polyolefin to be modified with a carboxylic acidis the same as described above. The carboxylic acid to be used formodification is the same as that used for modification of theacid-modified cycloolefin copolymer.

Among these resin components, carboxylic acid-modified polyolefins arepreferred, and carboxylic acid-modified polypropylene is furtherpreferred.

The sealant layer 4 may be formed from one resin component alone, or maybe formed from a blend polymer obtained by combining two or more resincomponents. Further, the sealant layer 4 may include only one layer, ortwo or more layers formed of the same resin component or different resincomponents.

While the thickness of the sealant layer 4 is not particularly limitedas long as a function as a sealant layer is performed, and the batterypackaging material satisfies the above-mentioned properties, it is, forexample, about 10 to 100 μm, preferably about 15 to 50 μm.

[Adhesive Layer 5]

In the battery packaging materials according to the first aspect and thesecond aspect of the present invention, the adhesive layer 5 is a layerthat is provided between the metal layer 3 and the sealant layer 4 asnecessary for strongly bonding these layers to each other.

The adhesive layer 5 is formed from an adhesive capable of bonding themetal layer 3 and the sealant layer 4 to each other. The bondingmechanism, the kind of the adhesive agent component, and so on for theadhesive agent to be used for formation of the adhesive layer 5 are thesame as those for the adhesive layer 2. The adhesive component to beused in the adhesive layer 5 is preferably a polyolefin-based resin,further preferably a carboxylic acid-modified polyolefin, especiallypreferably carboxylic acid-modified polypropylene.

While the thickness of the adhesive layer 5 is not particularly limitedas long as a function as an adhesive layer is performed, and the batterypackaging material satisfies the above-mentioned properties, it is, forexample, about 2 to 50 μm, preferably about 15 to 30 μm.

[Coating Layer 6]

In the battery packaging materials according to the first aspect and thesecond aspect of the present invention, a coating layer 6 may beprovided on the base material layer 1 (on the base material layer 1 on aside opposite to the metal layer 3) as necessary for the purpose of, forexample, improving designability, electrolytic solution resistance,scratch resistance and moldability. The coating layer 6 is a layer thatis situated at an outermost layer when a battery is assembled.

The coating layer 6 can be formed from, for example, polyvinylidenechloride, a polyester resin, a urethane resin, an acrylic resin, anepoxy resin, or the like. Preferably, the coating layer 6 is formed froma two-liquid curable resin among the resin described above. Examples ofthe two-liquid curable resin that forms the coating layer 6 includetwo-liquid curable urethane resins, two-liquid curable polyester resinsand two-liquid curable epoxy resins. The coating layer 6 may contain amatting agent.

Examples of the matting agent include fine particles having a particlesize of about 0.5 nm to 5 μm. The material of the matting agent is notparticularly limited, and examples thereof include metals, metal oxides,inorganic substances and organic substances. The shape of the mattingagent is not particularly limited, and examples thereof include aspherical shape, a fibrous shape, a plate shape, an amorphous shape anda balloon shape. Specific examples of the matting agent include talc,silica, graphite, kaolin, montmorilloide, montmorillonite, syntheticmica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesiumhydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide,antimony oxide, titanium oxide, cerium oxide, calcium sulfate, bariumsulfate, calcium carbonate, calcium silicate, lithium carbonate, calciumbenzoate, calcium oxalate, magnesium stearate, alumina, carbon black,carbon nanotubes, high-melting-point nylons, crosslinked acrylics,crosslinked styrenes, crosslinked polyethylenes, benzoguanamine, gold,aluminum, copper and nickel. These matting agents may be used alone, ormay be used in combination of two or more thereof. Among these mattingagents, silica, barium sulfate and titanium oxide are preferred from theviewpoint of dispersion stability, costs and so on. The surface of thematting agent may be subjected to various kinds of surface treatmentssuch as an insulation treatment and dispersibility enhancing treatment.

The method for forming the coating layer 6 is not particularly limited,and examples thereof include a method in which a two-liquid curableresin for forming the coating layer 6 is applied to one of the surfacesof the base material layer 1. In the case where a matting agent isblended, the matting agent may be added to and mixed with the two-liquidcurable resin, followed by applying the mixture.

While the thickness of the coating layer 6 is not particularly limitedas long as the above-mentioned function as the coating layer 6 isperformed, and the battery packaging material satisfies theabove-mentioned properties, it is, for example, about 0.5 to 10 μm,preferably about 1 to 5 μm.

4. Method for Producing Battery Packaging Material

While the method for producing the battery packaging material of each ofthe first aspect and the second aspect of the present invention is notparticularly limited as long as a laminate including layers each havingpredetermined composition is obtained, and for example, the followingmethod is shown as an example.

First, a laminate with the base material layer 1, the adhesive layer 2provided as necessary, and the metal layer 3 laminated in this order(hereinafter, the laminate may be described as a “laminate A”) isformed. Specifically, the laminate A can be formed by a dry laminationmethod in which an adhesive agent to be used for formation of theadhesive layer 2 is applied onto the base material layer 1 or the metallayer 3 the surface of which is subjected to a chemical conversiontreatment as necessary, using a coating method such as an extrusionmethod, a gravure coating method or a roll coating method, and dried,the metal layer 3 or the base material layer 1 is then laminated, andthe adhesive layer 2 is cured.

Then, the sealant layer 4 is laminated on the metal layer 3 of thelaminate A. When the sealant layer 4 is laminated directly on the metallayer 3, a resin component that forms the sealant layer 4 may be appliedonto the metal layer 3 of the laminate A by a method such as a gravurecoating method or a roll coating method. When the adhesive layer 5 isprovided between the metal layer 3 and the sealant layer 4, mentioned isprovided, for example, by (1) a method in which the adhesive layer 5 andthe sealant layer 4 are co-extruded to be laminated on the metal layer 3of the laminate A (co-extrusion lamination method); (2) a method inwhich the adhesive layer 5 and the sealant layer 4 are laminated to forma laminate separately, and the laminate is laminated on the metal layer3 of the laminate A by a thermal lamination method; (3) a method inwhich an adhesive agent for formation of the adhesive layer 5 islaminated on the metal layer 3 of the laminate A by, for example, amethod of applying the adhesive agent onto the metal layer 3 with anextrusion method or solution coating, drying at a high temperature andbaking, and the sealant layer 4 formed in a sheet shape beforehand islaminated on the adhesive layer 5 by a thermal lamination method; and(4) a method in which the melted adhesive layer 5 is poured between themetal layer 3 of the laminate A and the sealant layer 4 formed in asheet shape beforehand, and simultaneously the laminate A and thesealant layer 4 are bonded together with the adhesive layer 5 interposedtherebetween (sandwich lamination method).

When the coating layer 6 is provided, the coating layer 6 is laminatedon a surface of the base material layer 1 on a side opposite to themetal layer 3. The coating layer 6 can be formed by, for example,coating a surface of the base material layer 1 with the resin that formsthe coating layer 6. The order of the step of laminating the metal layer3 on a surface of the base material layer 1 and the step of laminatingthe coating layer 6 on a surface of the base material layer 1 is notparticularly limited. For example, the coating layer 6 may be formed ona surface of the base material layer 1, followed by forming the metallayer 3 on a surface of the base material layer 1 on a side opposite tothe coating layer 6.

A laminate including the base material layer 1, the adhesive layer 2provided as necessary, the metal layer 3, the surface of which issubjected to a chemical conversion treatment as necessary, the adhesivelayer 5 provided as necessary, the sealant layer 4, and the coatinglayer 6 provided as necessary, in this order, is formed in the mannerdescribed above, and the laminate may be further subjected to a heatingtreatment of hot roll contact type, hot air type, near- or far-infraredtype, or the like for strengthening the adhesion of the adhesive layer 2and the adhesive layer 5 provided as necessary. As conditions for such aheating treatment, for example, the temperature is 150 to 250° C., andthe time is 1 to 5 minutes.

In the battery packaging materials according to the first aspect and thesecond aspect of the present invention, the layers that form thelaminate may be subjected to a surface activation treatment such as acorona treatment, a blast treatment, an oxidation treatment or an ozonetreatment as necessary for improving or stabilizing film formability,lamination processing and final product secondary processing (pouchingand embossing molding) suitability, and the like.

5. Use of Battery Packaging Material

The battery packaging materials according to the first aspect and thesecond aspect of the present invention are each used as a packagingmaterial for hermetically sealing and storing battery elements such as apositive electrode, a negative electrode and an electrolyte.

Specifically, a battery element including at least a positive electrode,a negative electrode and an electrolyte is covered with the batterypackaging material according to each of the first aspect and the secondaspect of the present invention such that a flange portion (region wheresealant layers are in contact with each other) can be formed on theperiphery of the battery element while a metal terminal connected toeach of the positive electrode and the negative electrode protrudes tothe outside, and sealant layers at the flange portion are heat-sealedwith each other for hermetical sealing, thereby providing a batteryusing a battery packaging material. When the battery element is storedusing the battery packaging material according to each of the firstaspect and the second aspect of the present invention, the batterypackaging material according to each of the first aspect and the secondaspect of the present invention is used such that the sealant portion ison the inner side (surface in contact with the battery element).

The battery packaging materials according to the first aspect and thesecond aspect of the present invention may be used for either a primarybattery or a secondary battery, but is preferably used for a secondarybattery. The type of the secondary battery to which the batterypackaging materials according to the first aspect and the second aspectof the present invention are applied is not particularly limited, andexamples thereof include lithium ion batteries, lithium ion polymerbatteries, lead storage batteries, nickel-hydrogen storage batteries,nickel-cadmium storage batteries, nickel-iron storage batteries,nickel-zinc storage batteries, silver oxide-zinc storage batteries,metal-air batteries, polyvalent cation batteries, condensers andcapacitors. Among these secondary batteries, preferred subjects to whichthe battery packaging materials according to the first aspect and thesecond aspect of the present invention are applied include lithium ionbatteries and lithium ion polymer batteries.

EXAMPLES

The first aspect and the second aspect of the present invention will bedescribed in detail below by way of examples and comparative examples.It is to be noted that the present invention is not limited to examples.

Examples 1A to 8A and Comparative Examples 1A to 4A

<Production of Battery Packaging Material>

A battery packaging material including a laminate with a base materiallayer 1, an adhesive layer 2, a metal layer 3, an adhesive layer 5 and asealant layer 4 laminated in this order was produced by laminating theadhesive layer 5 and the sealant layer 4 by a thermal lamination methodto a laminate with the base material layer 1, the adhesive layer 2 andthe metal layer 3 laminated in this order. Details of the layers thatform the battery packaging material, and production conditions are asshown below.

<Base Material Layer 1>

Details of nylon A, nylon B, polybutylene terephthalate A (PBT-A),polybutylene terephthalate B (PBT-B) and polyethylene terephthalate(PET) which were used for the base material layer 1 are shown below. Thetensile rupture strength and the tensile rupture elongation shown inTable 1 were each measured by a method conforming to JIS K7127.

(Nylon-A and Nylon-B)

An unstretched raw film formed of a raw material mainly composed ofnylon 6 was simultaneously biaxially stretched by a tubular method, andthen heat-treated at 200° C. to produce a nylon film. The nylon-A filmwas produced under the condition of a draw ratio of 3.0 in the machinedirection (MD) and 3.3 in the traverse direction (TD), and the nylon-Bfilm was produced under the condition of a draw ratio of 2.8 in themachine direction (MD) and 3.0 in the traverse direction (TD).

(PBT-A, -B)

An unstretched raw film formed of a raw material mainly composed of aresin with 8% by weight of polyethylene terephthalate added topolybutylene terephthalate was simultaneously biaxially stretched by atubular method, and then heat-treated at 205° C. to produce a PBT film.The PBT-A film was produced under the condition of a draw ratio of 3.8in the machine direction (MD) and 3.8 in the traverse direction (TD),and the PBT-B film was produced under the condition of a draw ratio of3.0 in the machine direction (MD) and 3.0 in the traverse direction(TD).

(PET)

An unstretched raw film formed of a raw material mainly composed ofpolyethylene terephthalate was sequentially biaxially stretched by atenter method, and then heat-treated at 210° C. to produce a PET film.The PET film was produced under the condition of a draw ratio of 3.2 inthe machine direction (MD) and 3.2 in the traverse direction (TD).

TABLE 1A Tensile rupture Tensile rupture strength [MPa] elongation [%]MD TD MD TD Nylon-A 286 348 110 85 Nylon-B 264 283 174 136 PBT-A 207 250125 105 PBT-B 168 213 129 91 PET 240 253 135 127<Metal Layer 3>

Aluminum foils (ALM1: 8021 material, ALM2: 8079 material and ALM3: 1N30material) having the properties shown in Table 2A below were each used.The 0.2% yield strength, tensile rupture strength and tensile ruptureelongation are each measured by a tensile test defined in JIS Z 2241(total elongation method).

TABLE 2A Tensile rupture strength Tensile rupture elongation 0.2% Yieldstrength [MPa] [%] [N/mm2] MD TD MD TD MD TD ALM1 109.0 101.9 11.2 11.675.5 73.3 ALM2 81.0 81.1 11.1 10.9 38.3 40.3 ALM3 75.1 73.3 7.8 6.7 33.635.2<Adhesive Layer 2>

For the adhesive layer 2 for bonding the base material layer 1 and themetal layer 3 to each other, the following adhesive A and adhesive Bwere used.

(Adhesive A)

A urethane resin-based adhesive obtained by mixing in a ratio of 1:3 apolyol compound having a glass transition point of −5 to 5° C., a weightaverage molecular weight of 10 to 40×10³ and a hydroxyl group equivalentof 0.7 to 1.9/mol and an aromatic isocyanate mainly composed of atrimethylolpropane (TMP) adduct of toluene diisocyanate (TDI) was used.

(Adhesive B)

A urethane resin-based adhesive obtained by mixing in a ratio of 1:3 apolyol compound having a glass transition point of −15 to −5° C., aweight average molecular weight of 10 to 10×10³ and a hydroxyl groupequivalent of 0.7 to 1.9/mol and an aromatic isocyanate mainly composedof an isocyanate-modified product of toluene diisocyanate (TDI) wasused.

<Coating Layer 6>

The coating layer 6 is a layer formed in Example 8A for the purpose ofimproving the moldability of the battery packaging material. An epoxyresin having bisphenol A as a unit in the backbone was applied in acoating amount of 2.5 g/m² to the base material layer 1, dried, and thenheated at 190° C. for 2 minutes to form the coating layer 6 as a curedfilm.

First, a laminate with the base material layer 1, the adhesive layer 2and the metal layer 3 laminated in this order was prepared using theabove layers. Specifically, the adhesive layer 2 composed of atwo-liquid urethane adhesive agent including a polyester-based mainagent and an isocyanate-based curing agent was formed in a thickness of3 μm on one surface (corona-treated) of the base material layer 1, andbonded to a chemically converted surface of the metal layer 3 bypressurization and heating to prepare a laminate with the base materiallayer 1, the adhesive layer 2 and the metal layer 3 laminated in thisorder.

Separately, an acid-modified polypropylene resin [unsaturated carboxylicacid-graft-modified random polypropylene graft-modified with anunsaturated carboxylic acid (hereinafter, referred to as PPa)] forforming the adhesive layer 5 and polypropylene [random copolymer(hereinafter, referred to as PP)] for forming the sealant layer 4 wereco-extruded to prepare a two-layer co-extruded film composed of theadhesive layer 5 and the sealant layer 4.

The prepared two-layer co-extruded film was then superimposed on theprepared laminate including the base material layer 1, the adhesivelayer 2 and the metal layer 3 in such a manner that the adhesive layer 5of the two-layer co-extruded film was in contact with the metal layer ofthe laminate, and thermal lamination was performed by applying heat sothat the temperature of the metal layer 3 was 120° C., thereby obtaininga laminate with the base material layer 1, the adhesive layer 2, themetal layer 3, the adhesive layer 5 and the sealant layer 4 laminated inthis order. The obtained laminate was temporarily cooled, then heated to180° C., and held at this temperature for 1 minute to be heat-treated,thereby obtaining a battery packaging material in each of Examples 1A to8A and Comparative Examples 1A to 4A. In Example 8A, the coating layer 6was formed on a surface of the base material layer 1 in the obtainedlaminate to obtain a battery packaging material.

The laminated structures of the battery packaging materials prepared inExamples 1A to 8A and Comparative Examples 1A to 4A and the thicknessesof the layers in the battery packaging materials are as follows.

Example 1A

Nylon-A (25 μm)/adhesive A (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Example 2A

Nylon-A (25 μm)/adhesive A (3 μm)/ALM 1 (50 μm)/adhesive layer 5 (30μm)/sealant layer 4 (30 μm)

Example 3A

Nylon-A (15 μm)/adhesive A (3 μm)/ALM 1 (35 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Example 4A

Nylon-A (15 μm)/adhesive A (3 μm)/ALM 2 (35 μm)/adhesive layer 5 (15μm)/sealant layer 4 (15 μm)

Example 5A

PBT-A (20 μm)/adhesive A (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Example 6A

PET (12 μm)/adhesive A (3 μm)/nylon A (15 μm)/adhesive A (3 μm)/ALM 1(40 μm)/adhesive layer 5 (20 μm)/sealant layer 4 (20 μm)

Example 7A

Nylon-B (25 μm)/adhesive B (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Example 8A

Coating layer 6 (2 μm)/nylon-B (25 μm)/adhesive A (3 μm)/ALM 1 (40μm)/adhesive layer 5 (20 μm)/sealant layer 4 (20 μm)

Comparative Example 1A

Nylon-B (25 μm)/adhesive A (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Comparative Example 2A

PBT-B (12 μm)/adhesive A (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Comparative Example 3A

PET (12 μm)/adhesive A (3 μm)/ALM 1 (40 μm)/adhesive layer 5 (20μm)/sealant layer 4 (20 μm)

Comparative Example 4A

Nylon-A (15 μm)/adhesive A (3 μm)/ALM 3 (35 μm)/adhesive layer 5 (15μm)/sealant layer 4 (15 μm)

<Measurement of Tensile Rupture Strength and Tensile Rupture Elongation>

The stress in elongation by 40% and the stress in elongation by 10% inthe MD direction and the TD direction in each of the battery packagingmaterials obtained as described above were each measured by a methodconforming to JIS K7127. As measurement conditions, the sample width was15 mm, the gauge length was 50 mm, and the tension speed was 100mm/minute. The results are shown in Table 3A.

<Evaluation of Moldability>

The battery packaging material obtained as described above was cut toprepare a strip piece of 120×80 mm, and the strip piece was used as atest sample. A straight mold including a rectangular male mold of 30×50mm, and a female mold with a clearance of 0.5 mm from the male mold wasprovided, the test sample was placed on the female mold in such a mannerthat the heat-adhesive resin layer was situated on the male mold side,the test sample was pressed at a pressing pressure (surface pressure) of0.1 MPa in such a manner that the molding depths were 6 mm and 7 mm,respectively, and cold molding (draw-in one-step molding) was performed.Presence/absence of pinholes and cracks in the metal layer in the moldedbattery packaging material was checked, and the ratio of generation (%)of pinholes and cracks was calculated. For the ratio of generation ofpinholes and cracks, a test sample having at least one pinhole or crackafter being molded as described above was discriminated as a moldingdefective product, and the ratio of molding defective products occurringat the time of molding 30 test samples under the above-mentionedconditions was determined. The results are shown in Table 3A.

TABLE 3A Tensile rupture Tensile rupture Stress in elongation Stress inelongation strength elongation by 10% by 40% Ratio of generation ofpinholes [MPa] [%] [MPa] [MPa] and cracks [%] MD TD MD TD MD TD MD TD AB A + B 6 mm 7 mm Example 1A 72.6 86.8 101.9 90.9 52.8 49.3 67.0 73.41.27 1.49 2.76 0 0 Example 2A 76.5 88.8 86.4 85.9 55.7 52.0 69.6 72.61.25 1.40 2.65 0 0 Example 3A 79.1 72.4 94.1 88.5 61.6 41.4 76.2 60.81.24 1.47 2.71 0 0 Example 4A 62.1 69.5 94.5 99.6 50.5 48.2 60.3 65.21.19 1.35 2.55 0 10 Example 5A 66.1 75.8 75.0 70.3 49.7 49.3 61.3 66.01.23 1.34 2.57 0 17 Example 6A 53.8 73.8 84.8 93.1 37.3 41.4 47.6 59.01.28 1.43 2.70 0 7 Example 7A 69.5 75.2 86.8 83.3 54.5 50.0 65.2 65.31.20 1.31 2.50 0 23 Example 8A 70.4 77.7 89.9 85.5 54.8 49.1 65.5 66.41.20 1.35 2.55 0 17 Comparative 66.8 70.6 83.3 85.3 54.0 48.8 64.1 63.01.19 1.29 2.48 10 67 Example 1A Comparative 63.0 66.2 45.0 58.0 50.052.1 57.9 63.9 1.16 1.23 2.38 67 83 Example 2A Comparative 62.4 71.940.7 52.2 55.6 55.1 62.2 69.7 1.12 1.26 2.38 73 100 Example 3AComparative 64.7 68.2 80.5 80.0 53.8 46.9 62.2 61.2 1.16 1.30 2.46 23 67Example 4A

The results in Table 3A show that even when the battery packagingmaterial was molded under a severe condition, i.e. at a molding depth of6 mm, the battery packaging materials of Examples 1A to 8A in which thebattery packaging material satisfied the relationship of A+B≥2.50 had nopinholes and cracks, suggesting that generation of pinholes and crackswas remarkably suppressed. Particularly, even when the battery packagingmaterial was molded under a more severe condition, i.e. at a moldingdepth of 7 mm, the battery packaging materials of Examples 1A to 3A inwhich the battery packaging material satisfied the relationship ofA+B≥2.65 had no pinholes and cracks, suggesting that generation ofpinholes and cracks was remarkably suppressed. The battery packagingmaterials of Comparative Examples 1A to 4A in which the batterypackaging material satisfied the relationship of A+B<2.50 had a highratio of generation of pinholes and cracks when molded at a moldingdepth of 6 mm, and was thus inferior in moldability to the batterypackaging materials of Examples 1A to 8A.

Examples 1B to 7B and Comparative Examples 1B to 4B

<Production of Battery Packaging Material>

A battery packaging material including a laminate with a base materiallayer 1, an adhesive layer 2, a metal layer 3, an adhesive layer 5 and asealant layer 4 laminated in this order was produced by laminating theadhesive layer 5 and the sealant layer 4 by a thermal lamination methodto a laminate with the base material layer 1, the adhesive layer 2 andthe metal layer 3 laminated in this order. Details of the layers thatform the battery packaging material, and production conditions are asshown below.

<Base Material Layer 1>

Details of a nylon film and a polyethylene terephthalate (PET) filmwhich were used for the base material layer 1 are shown below. Alaminate of PET and nylon was obtained by bonding a PET film and a nylonfilm to each other with an adhesive that formed the adhesive layer 2.

(Nylon Film)

An unstretched raw film formed of a raw material mainly composed ofnylon 6 was simultaneously biaxially stretched by a tubular method, andthen heat-treated at 200° C. to produce a nylon film. The nylon film wasproduced under the condition of a draw ratio of 3.0 in the machinedirection (MD) and 3.3 in the traverse direction (TD).

(PET Film)

An unstretched raw film formed of a raw material mainly composed ofpolyethylene terephthalate was sequentially biaxially stretched by atenter method, and then heat-treated at 210° C. to produce a PET film.The PET film was produced under the condition of a draw ratio of 3.2 inthe machine direction (MD) and 3.2 in the traverse direction (TD).

<Metal Layer 3>

Aluminum foils (8079 material) having the thicknesses and propertiesshown in Table 1B below were each used. The tensile rupture strength andthe tensile rupture elongation are each measured by a method conformingto JIS K7127. The 0.2% yield strength is a value measured by a tensiletest defined in JIS Z 2241 (total elongation method).

TABLE 1B Tensile rupture strength Tensile rupture elongation 0.2% Yieldstrength Thickness of [MPa] [%] [N/mm2] metal layer MD TD MD TD MD TD 40μm 83.0 81.9 12.9 12.2 37.3 39.5 35 μm 80.8 81.3 11.3 10.8 37.9 39.9 30μm 82.8 82.5 10.5 9.8 38.4 41.1<Adhesive Layer 2>

An acid-modified polypropylene composed of an ethylene-propylenecopolymer (random copolymerization type) having a melting point of 142°C. and a MFR (230° C.) of 6 g/10 minutes was used for the adhesive layer2 for bonding the base material layer 1 and the metal layer 3.

<Sealant Layer 4>

A propylene-ethylene copolymer having a melting point of 132° C. and aMFR (230° C.) of 12 g/10 minutes was used for the sealant layer 4.

<Coating Layer>

The coating layer is a layer formed in Example 6B for the purpose ofimproving the moldability of the battery packaging material. An epoxyresin having bisphenol A as a unit in the backbone was applied in acoating amount of 2.5 g/m² to the base material layer 1, dried, and thenheated at 190° C. for 2 minutes to form the coating layer as a curedfilm.

First, a laminate with the base material layer 1, the adhesive layer 2and the metal layer 3 laminated in this order was prepared using theabove layers. Specifically, the adhesive layer 2 was formed in athickness of 3 μm on one surface of the base material layer 1, andbonded to a chemically converted surface of the metal layer 3 bypressurization and heating to prepare a laminate with the base materiallayer 1, the adhesive layer 2 and the metal layer 3 laminated in thisorder. Separately, an acid-modified polypropylene resin (unsaturatedcarboxylic acid-graft-modified random polypropylene graft-modified withan unsaturated carboxylic acid) for forming the adhesive layer 5 andpolypropylene (random copolymer) for forming the sealant layer 4 wereco-extruded to prepare a two-layer co-extruded film composed of theadhesive layer 5 and the sealant layer 4.

The prepared two-layer co-extruded film was then superimposed on theprepared laminate including the base material layer 1, the adhesivelayer 2 and the metal layer 3 in such a manner that the adhesive layer 5of the two-layer co-extruded film was in contact with the metal layer ofthe laminate, and thermal lamination was performed by applying heat sothat the temperature of the metal layer 3 was 120° C., thereby obtaininga laminate with the base material layer 1, the adhesive layer 2, themetal layer 3, the adhesive layer 5 and the sealant layer 4 laminated inthis order. The obtained laminate was temporarily cooled, then heated to180° C., and held at this temperature for 1 minute to be heat-treated,thereby obtaining a battery packaging material in each of Examples 1B to7B and Comparative Examples 1B to 4B.

The laminated structures of the battery packaging materials prepared inExamples 1B to 7B and Comparative Examples 1B to 4B and the thicknessesof the layers in the battery packaging materials are as follows.

Example 1B

Nylon (15 μm)/adhesive layer 2 (3 μm)/metal layer 3 (40 μm)/adhesivelayer 5 (25 μm)/sealant layer 4 (25 μm)

Example 2B

Nylon (25 μm)/adhesive layer 2 (3 μm)/metal layer 3 (40 μm)/adhesivelayer 5 (25 μm)/sealant layer 4 (25 μm)

Example 3B

PET (12 μm)/adhesive (3 μm)/nylon (15 μm)/adhesive layer 2 (3 μm)/metallayer 3 (40 μm)/adhesive layer 5 (25 μm)/sealant layer 4 (25 μm)

Example 4B

PET (12 μm)/adhesive layer 2 (3 μm)/metal layer 3 (40 μm)/adhesive layer5 (25 μm)/sealant layer 4 (25 μm)

Example 5B

Nylon (15 μm)/adhesive layer 2 (3 μm)/metal layer 3 (35 μm)/adhesivelayer 5 (25 μm)/sealant layer 4 (25 μm)

Example 6B

Coating layer (3 μm)/nylon (25 μm)/adhesive layer 2 (3 μm)/metal layer 3(40 μm)/adhesive layer 5 (25 μm)/sealant layer 4 (25 μm)

Example 7B

Nylon (15 μm)/adhesive layer 2 (3 μm)/metal layer 3 (30 μm)/adhesivelayer 5 (25 μm)/sealant layer 4 (25 μm)

Comparative Example 1B

PET (12 μm)/adhesive (3 μm)/nylon (25 μm)/adhesive layer 2 (3 μm)/metallayer 3 (40 μm)/adhesive layer 5 (25 μm)/sealant layer 4 (25 μm)

Comparative Example 2B

Nylon (25 μm)/adhesive layer 2 (3 μm)/metal layer 3 (35 μm)/adhesivelayer 5 (25 μm)/sealant layer 4 (25 μm)

Comparative Example 3B

PET (12 μm)/adhesive (3 μm)/nylon (15 μm)/adhesive layer 2 (3 μm)/metallayer 3 (30 μm)/adhesive layer 5 (25 μm)/sealant layer 4 (25 μm)

Comparative Example 4B

Nylon (15 μm)/adhesive layer 2 (3 μm)/metal layer 3 (30 μm)/adhesivelayer 5 (10 μm)/sealant layer 4 (10 μm)

<Measurement of Stress in Elongation by 10%>

Stresses A1 and B1 in elongation by 10% in the MD direction and the TDdirection in each of the battery packaging materials obtained asdescribed above, and stresses A2 and B2 in elongation by 10% in the MDdirection and the TD direction in the base material layer 1 used wereeach measured by a method conforming to JIS K7127. As measurementconditions, the sample width was 15 mm, the gauge length was 50 mm, andthe tension speed was 100 mm/minute. The results are shown in Table 2B.

<Measurement of Dynamic Friction Coefficient>

For each of a surface of the base material layer (the surface of thecoating layer in Example 6B) and a surface of the sealant layer in eachof the battery packaging materials obtained as described above, thedynamic friction coefficient was measured by a method conforming to JISK7125. The results are shown in Table 2B.

<Evaluation of Curling after Molding>

The battery packaging material obtained as described above was cut toprepare a strip piece of 150×100 mm, and the strip piece was used as atest sample. A straight mold including a rectangular male mold of 30×50mm, and a female mold with a clearance of 0.5 mm from the male mold wasprepared, the test sample was placed on the female mold in such a mannerthat the sealant layer 4 was situated on the male mold side, the testsample was pressed at a pressing pressure (surface pressure) of 0.1 MPain such a manner that the molding depth was 6 mm, and cold molding(draw-in one-step molding) was performed. Details of the position atwhich molding was performed are as shown in FIG. 6. Molding wasperformed at a position where the shortest distance d between arectangular molded part M and an end part P of a battery packagingmaterial 10 is 25 mm as shown in FIG. 6. Next, the battery packagingmaterial 10 after molding was placed on a horizontal surface 20 in amanner as shown in FIG. 7, and the maximum value t of a distance betweenthe horizontal surface 20 and the end part P in a vertical direction ywas defined as the maximum height of a curled portion. The evaluationcriteria for curling after molding are as described below. The resultsare shown in Table 2B.

◯: The value t is 0 mm or more and less than 10 mm, curling is small,and productivity is hardly deteriorated.

Δ: The value t is 10 mm or more and less than 20 mm, and curling isslightly large, but deterioration of productivity is small.

x: The value t is 20 mm or more and less than 30 mm, curling is large,and deterioration of productivity is large.

xx: The value t is 30 mm or more, curling is very large, anddeterioration of productivity is very large.

TABLE 2B Dynamic friction Dynamic coefficient friction Stress inelongation by 10% [N/15 mm] of surface coefficient Battery packagingBase material of base of surface material layer Ratio of material ofsealant Results of A1 B1 A2 B2 (A1 − A2)/ layer layer Ratio ofevaluation (MD) (TD) (MD) (TD) A1 − A2 B1 − B2 (B1 − B2) (C) (D) C/D oncurling Example 1B 81.7 72.9 16.0 13.7 65.7 59.2 1.11 0.23 0.12 1.92 ∘Example 2B 87.0 79.6 25.6 25.1 61.4 54.5 1.13 0.33 0.25 1.32 Δ Example3B 101.2 95.4 40.7 39.7 60.5 55.7 1.09 0.28 0.13 2.15 Δ Example 4B 84.783.9 23.4 24.1 61.3 59.8 1.03 0.19 0.13 1.46 ∘ Example 5B 80.1 71.5 16.013.7 64.1 57.8 1.11 0.20 0.11 1.82 ∘ Example 6B 87.0 79.6 25.6 24.1 61.455.5 1.11 0.08 0.10 0.80 ∘ Example 7B 76.5 64.6 16.0 13.7 60.5 50.9 1.190.20 0.13 1.54 Δ Comparative 104.7 100.3 48.5 47.7 56.2 52.6 1.07 0.260.12 2.17 x Example 1B Comparative 86.1 74.5 25.6 25.1 60.5 49.4 1.220.21 0.13 1.62 x Example 2B Comparative 81.2 85.4 40.7 39.7 40.5 45.70.89 0.25 0.12 2.08 xx Example 3B Comparative 66.5 61.6 16.0 13.7 50.547.9 1.05 0.22 0.11 2.00 xx Example 4B

The results in Table 2B show that even when the battery packagingmaterial was molded under a severe condition, i.e. at a molding depth of6 mm, the battery packaging materials of Examples 1B to 7B in which thebattery packaging material satisfied the relationships of (A1−A2)≥60N/15 mm and (B1−B2)≥50 N/15 mm. The battery packaging materials ofComparative Examples 1B to 4B in which the battery packaging materialdid not satisfy both of the above-mentioned relationships weresignificantly curled when molded at a molding depth of 6 mm, and werethus inferior in moldability to the battery packaging materials ofExamples 1B to 7B.

DESCRIPTION OF REFERENCE SIGNS

-   -   1: Base material layer    -   2: Adhesive layer    -   3: Metal layer    -   4: Sealant layer    -   5: Adhesive layer    -   10: Battery packaging material    -   M: Molded part    -   P: End part

The invention claimed is:
 1. A battery packaging material comprising alaminate in which at least a base material layer, a metal layer, and asealant layer are laminated in this order, wherein the battery packagingmaterial satisfies the relationships of:(A1−A2)≥60 N/15 mm; and(B1−B2)≥50 N/15 mm, where: A1 is a stress in elongation by 10% in the MDdirection and B1 is a stress in elongation by 10% in the TD direction inthe laminate, and A2 is a stress in elongation by 10% in the MDdirection and B2 is a stress in elongation by 10% in the TD direction inthe base material layer, and wherein the base material layer consistsessentially of at least one of polyamide resin and polyester resin, andoptionally an adhesive.
 2. The battery packaging material according toclaim 1, wherein a ratio of (A1−A2) to (B1−B2) satisfies therelationship of (A1−A2)/(B1−B2)=1.00 to 1.20.
 3. The battery packagingmaterial according to claim 1, wherein, when C is a dynamic frictioncoefficient of a surface of the base material layer and D is a dynamicfriction coefficient of a surface of the sealant layer, the batterypackaging material satisfies the relationships of:C≤0.3;D≤0.3; andC/D=0.5 to 2.5.
 4. The battery packaging material according claim 1,wherein the battery packaging material is a battery packaging materialfor deep drawing which is molded with a molding depth of 4 mm or more.5. The battery packaging material according to claim 1, wherein thelaminate has a thickness of 120 μm or less.
 6. The battery packagingmaterial according to claim 1, wherein at least one surface of the metallayer is subjected to a chemical conversion treatment.
 7. The batterypackaging material according to claim 1, wherein the battery packagingmaterial is a packaging material for a secondary battery.
 8. A batterycomprising a battery element including at least a positive electrode, anegative electrode, and an electrolyte being stored in the batterypackaging material according to claim
 1. 9. The battery packagingmaterial according to claim 1, further comprising an adhesive layerbetween the metal layer and the sealant layer.
 10. The battery packagingmaterial according to claim 1, wherein the sealant layer is formed oftwo or more layers comprising an identical resin component or differentresin components.
 11. The battery packaging material according to claim1, wherein the metal layer has a thickness of about 10 μm to about 50μm.
 12. A method for producing the battery packaging material accordingto claim 1, the method comprising: preparing the laminate in which atleast the base material layer, the metal layer, and the sealant layerare laminated in this order.
 13. The method according to claim 12,further comprising applying an adhesive layer between the metal layerand the sealant layer.
 14. The method according to claim 13, wherein theadhesive layer and the sealant layer are co-extruded and laminated onthe metal layer.
 15. The method according to claim 12, wherein thesealant layer is formed of two or more layers comprising an identicalresin component or different resin components.